The San Francisco 49ers' Chris Culliver has been sued by an SUV driver accusing the cornerback of threatening a 15-year-old with brass knuckles and using a racial slur, in the midst of trying to flee the scene of a crash.Culliver, 25, has already been arrested and pleaded not guilty to hit-and-run and weapons charges in connection with that March 28 collision in San Jose, in which police say he hit a cyclist and then, in trying to flee, the SUV as well.The SUV driver Marc Santos' family's suit accuses Culliver of assault, battery, intentionally inflicting emotional distress and negligently using his car and brass knuckles. It demands damages and punitive damages. - READ: Lawsuit vs. Chris CulliverAttempts to locate a lawyer for Culliver were not immediately successful. A lawyer for Marc Santos and his family, Braid Pezzaglia, told NBC Bay Area he is not yet aware of a defense lawyer in the suit he filed for the Santos family.A 49ers spokesman declined to comment on the litigation to NBC Bay Area on Friday. Culliver's public relations company, Creative Edge, emailed NBC Bay Area on Friday that "we are not at liberty to have any comment at this time." - 49ers' Culliver...